Ink jet printing is a non-impact method for producing images by the deposition of ink droplets in a pixel-by-pixel manner to an image-recording element in response to digital signals. There are various methods which may be utilized to control the deposition of ink droplets on the image-recording element to yield the desired image. In one process, known as continuous ink jet, a continuous stream of droplets is charged and deflected in an imagewise manner onto the surface of the image-recording element, while unimaged droplets are caught and returned to an ink sump. In another process, known as drop-on-demand ink jet, individual ink droplets are projected as needed onto the image-recording element to form the desired image. Common methods of controlling the projection of ink droplets in drop-on-demand printing include piezoelectric transducers and thermal bubble formation. Ink jet printers have found broad applications across markets ranging from industrial labeling to short run printing to desktop document and pictorial imaging.
U.S. Pat. No. 5,738,716 relates to a color pigmented ink jet ink set comprising a bridged aluminum phthalocyanine pigment, Pigment Red 122, Pigment Yellow 74, and Pigment Black 7. However, there is a problem with this ink jet ink set in that the inks fade under typical outdoor weather conditions. It is an object of this invention to provide an ink jet ink set which exhibits both superior outdoorfastness and lightfastness.